Long term evolution (LTE, Long Term Evolution) is a new technology evolution direction introduced in communications technologies at present. A high rate packet data (HRPD, High Rate Packet Data) technology is applied in a code division multiple access (CDMA 2000, Code Division Multiple Access 2000) network to bear high-speed data services. Deployment of an LTE network as a newly established network is expanded gradually. At present, more frequently, the LTE network is used as a hot spot to cover and be superimposed on a conventional HRPD network. When a terminal performing a service enters an area without coverage of the LTE network and only with coverage of the HRPD network from an area with coverage of the LTE network, a handover from the LTE network to the HRPD network is needed, so as to avoid terminal service interruption.
At present, the handover from the LTE network to the HRPD network includes two types of handovers: an optimized handover and a non-optimized handover. For the non-optimized handover, the terminal has no capability of supporting the optimized handover, but the terminal may self-decide whether to perform the handover. However, for the optimized handover, the terminal is required to have the capability of supporting the optimized handover (for example, supporting a pre-registration process), and a network side indicates the terminal to perform the optimized handover. The terminal supporting the optimized handover needs to wait for an indication of the network side before performing operations; therefore, if a handover indication sent by an Evolved Node B (eNB) is not received by the terminal, a subsequent handover process is not started by the terminal.
The inventor finds that, in some scenarios, the prior art is failed to implement a handover from a first network (such as the LTE network) to another network (such as the HRPD network).